Standard Life says it is drawing contingency plans to move some of its operations out of Scotland in the event it votes for independence.

The investment firm is one of Scotland's biggest employers with 5,000 people.

Though the firm that has been based in Scotland for 189 years is maintaining a strict policy of neutrality on the vote, it said Thursday it has a responsibility to its customers to take action to protect their interests.

The company says it has started work to establish additional registered companies to operate outside Scotland, "into which we could transfer parts of our operations if it was necessary to do so."

The vote has raised a number of issues for companies, including what sort of currency would be used.